Immunotherapy is a therapeutic strategy that takes advantage of the immune system by eliciting an immune response against diseases. Specifically, immunotherapies are employed to target cancer or the uncontrollable growth of cells. Two researchers, Dr. James Allison and Dr. Tasuku Honjo, were awarded the Nobel Prize in Physiology or Medicine for discovering two immunotherapies known as checkpoint inhibitors for solid cancer treatment. While immunotherapy has demonstrated efficient success in different cancer types, it is still limited in the treatment of more advanced cancers by several factors that promote tumor growth.
Immune cells in the body become polarized or changed to promote tumor progression. Tumors release specific proteins that reshape the body’s immune system. Unfortunately, eliminating healthy immune cells allows tumors to grow, leading to metastasis or cancer growing in secondary locations. One type of immune cell includes tissue-resident memory T cells, or memory killer cells, which reside in the tissue. Memory killer cells fight infection and can be found in different tissues throughout the body. While these cells are commonly useful to the immune system, they can also contribute to skin disorders and some cancers.
It has previously been demonstrated that these memory-killer cells respond to immunotherapy. However, it was unclear how they formed in tissues. Recently, research teams led by Drs. Beatrice Zitti and Elena Hoffer, at the Karolinska Institute in Sweden, investigated how these cells develop. Zitti, Hoffer, and colleagues studied memory killer cells in human skin. As described in the Immunity paper, the team collected human blood and skin from healthy volunteers and isolated the cells to determine how they were formed from the blood and developed in the tissue or skin. By analyzing the memory killer cells from the healthy donors, Zitti, Hoffer, and others were able to isolate specific genes required for development.
After testing a healthy donor sample, the research team conducted similar studies on patients with melanoma, a common skin cancer. Researchers have found vital factors necessary for the development of memory killer cells by comparing cells from a healthy donor and a patient with melanoma. After sampling the tumor, the researchers found that increased memory killer cells indicated a higher survival rate. However, memory-killer cells in the skin can still contribute to skin disease and cancer. Specifically, tumors can change healthy memory-killer cells to promote tumor progression. Therefore, researchers are further investigating how to balance the development of memory killer cells to maintain a healthy state.
Currently, Zitti, Hoffer, and colleagues are working to enhance immunotherapy by focusing on memory-killer cells. The findings reported in this paper are foundational. Memory killer cells are a standard cell population in the immune system that can affect the disease itself and the immunotherapy prescribed by the patient. We can improve treatments for cancer and other diseases, such as psoriasis, through knowledge of memory-killer cell development. These data will enhance therapy moving forward and provide insight into how the immune system functions.
Paper, Immunity, Karolinska Institute, Beatrice Zitti, Elena Hoffer, James Allison, Tasuku Honjo, Nobel Prize
